Abstract: An arithmetic unit for image transformation for transforming a fisheye image obtained by using a fisheye lens into a plane image for display, comprising: a first coordinate calculating unit for obtaining first projection coordinates derived by projecting coordinates on the plane image onto a fisheye image face as an imaginary object face; and a second coordinate calculating unit for obtaining second projection coordinates derived by projecting the first projection coordinates obtained by the first coordinate calculating unit onto the fisheye image face.